Research On Object Relational Mapping Mechanism In The Information System Development And Its Application

There are two important problems need to be solved in information system development, one is data storage and the other is the construction of business logic. Data storage problem is often solved by the relational database based on the relational model, and the construction of business logic is usually solved by using object-oriented technology based on object model.The relation model is based on the set of tables, mainly uses set theory and other mathematical theory to store data. The object model uses object as the basic unit of data model for describing the things. In the development of information system, when using object-oriented technology to establish the business logic, but using relational database for storage, the combination of the two models is not ideal and does not match the problem, for this mismatch problem, we usually use Object Relational Mapping(ORM) technology to solve.This paper aimes at three key problems which the ORM technology in information system development need to solve, namely the mapping mechanism between object model and relational model, the design of application program interface(API) which is the persistence layer providing to business layer, and the Performance optimization strategy adopted due to the negative effect which is generated by the introduction of the program running efficiency of the ORM technology. In this paper, the main work is as follows:Firstly, the object metadata model is established by the metadata technology including the packages, classes, class attributes, operations and associations and on. The metadata model is established including elements such as columns, tables, views, primary key, and foreign key and so on.The paper analyses entities, attributes and connections between entities and inheritance mapping methods. The mapping of object metadata model to relational metadata model is achieved through the instances using XML technology.Secondly, using the layering concept, the design of SMISDT(Small and Medium-sized Information System Development Toolkit) framework persistence Layer(Persistent Layer) interface based on object relationalmapping have been completed, including the object management, object mapping layer, data access layer interface design and data cache, data transaction processing function module interface design. The business layer does CRUD operations for persistent objects by calling the persistence layer interface.Thirdly, the Performance optimization strategy adopted due to the negative effect which is generated by the introduction of the program running efficiency of the ORM technology have been studied. Query mechanism based on semantic cache and the key problems of cache consistency maintenance have been introduced detailly.Finally, the implementation of SMISDT application framework has been completed. The main function settings and implementation of the SMISDT application framework such as database connection, cache feature configing,transaction processing, generating SQL and XML data resources stored procedures description have been introduced in detail. The SMISDT application framework has the characteristics of multi-functional, easy operation and high efficiency.